The main objective of this research program is to gain further basic knowledge concerning the possible physiological bases of adult learning and memory. The ontogenetic approach is utilized to examine the development of learning and memory capacities at the very early ages in order to determine how more complex learning and memory processes are formed. After determination is made of the chronological ages which are required for certain kinds of learning and memory capacities to be evidenced, treatments which appear to alter rates of central nervous system maturation will be administered and their effects upon the developing learning and memory capacities will be examined. Comparisons of these differentially treated animals at the times of onset of similar learning and memory abilities should provide evidence as to the factors underlying these capabilities.